Mobile Station Position Estimation Using Cell Landmarks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Satellite positioning systems face significant delays in signal acquisition due to large initial position uncertainty, which is exacerbated by the need for extensive searches in two-dimensional code-phase delay and Doppler frequency shift spaces, especially after a receiver cold start or signal loss, leading to increased power consumption and communication bandwidth usage.
Innovation Solution
A method that reduces initial position uncertainty by identifying the location of a serving cell and nearby landmarks, using this information to determine an initial estimate of the receiver's location, and then processing received signals to obtain a more precise estimate, while updating a position database with contemporaneous signal information to refine location calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large search space is used to ensure complete signal acquisition coverage, then signal acquisition reliability is improved, but signal acquisition time increases significantly
Solution Approach 1:
The patent applies preliminary action by using cell location information and landmark data to pre-determine an initial estimate of the receiver's position before signal acquisition begins. This preliminary position estimate allows the system to narrow down the search space in code-phase delay and Doppler frequency shift dimensions, thereby reducing signal acquisition time while maintaining reliability through subsequent refinement steps
2Loss of time
If assisted position location systems are used to reduce search space, then signal acquisition time is reduced, but communication bandwidth consumption and power usage increase
Solution Approach 1:
The patent implements self-service by enabling the mobile station to autonomously determine its initial position estimate using locally available cell location information and landmark data from its database, without requiring real-time communication with external assistance servers. This eliminates continuous messaging overhead and reduces both power consumption and communication bandwidth usage while achieving rapid signal acquisition
3Loss of time
If assisted position location systems are used to reduce search space, then signal acquisition time is reduced, but communication system bandwidth consumption increases
Solution Approach 1:
The mobile station autonomously utilizes pre-stored cell location information and landmark data to determine its initial position estimate, eliminating the need for real-time communication with external assistance entities. This self-service approach reduces communication bandwidth consumption by avoiding continuous messaging while still achieving reduced search space for signal acquisition
4Reliability
If a cold start condition occurs with no prior signal knowledge, then complete signal search capability is maintained, but signal acquisition delay increases to tens of seconds
Solution Approach 1:
Even in cold start conditions, the patent applies preliminary action by utilizing cell location information and landmark data to establish an initial position estimate before beginning the signal acquisition search. This preliminary estimation narrows the search space significantly compared to a complete blind search, reducing acquisition delay from tens of seconds to a much shorter duration while maintaining complete search capability through subsequent refinement
Data Source
AI summary
The subject matter disclosed herein relates to a system and method for reducing an initial position uncertainty of a mobile station. In one example, although claimed subject matter is not so limited, a process to improve an initial position estimate comprises identifying the locations of a serving cell and at least one other landmark proximate to a receiver and determining an initial estimate of the location of the receiver based, at least in part, on the identified locations of the serving cell and the at least one other landmark.